CVE-2026-44579: Next Denial of Service Vulnerability

HIGH
Advisory Identifier: GHSA-mg66-mrh9-m8jx
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CVSS 7.5
CWE-770
Published
Advisory Summary

CVE-2026-44579 is a HIGH (CVSS 7.5) denial of service vulnerability (CWE-770: Allocation of Resources Without Limits or Throttling) affecting Next libraries in the npm ecosystem. The issue involves next.js vulnerable to denial of service via connection exhaustion in applications using cache components. Remediation is available by upgrading affected packages to version 15.5.16, 16.2.5.

CVE-2026-44579 at a Glance

CVE Identifier CVE-2026-44579
GHSA Identifier GHSA-mg66-mrh9-m8jx
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-770: Allocation of Resources Without Limits or Throttling
Affected Product Next
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 7.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability High (A:H)

How to Fix CVE-2026-44579

To remediate this vulnerability, upgrade all affected Next dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

next fixed: 15.5.16 
npm install next@15.5.16
next fixed: 16.2.5 
npm install next@16.2.5
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls next

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-44579, inspect your project dependencies using npm:

npm ls next

Analyze the terminal output to locate any version of Next in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 15.5.16), your application is affected.

Note: The npm ls next command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-770: Allocation of Resources Without Limits or Throttling, where the product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated. In Next, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Impact Applications using Partial Prerendering through the Cache Components feature can be vulnerable to connection exhaustion through crafted POST requests to a server action. In affected configurations, a malicious request can trigger a request-body handling deadlock that leaves connections open for an extended period, consuming file descriptors and server capacity until legitimate users are denied service. ### Fix We now treat the header used for resuming Partial Prerendered requests as an internal-only header and strip it from untrusted incoming requests. This header should never be accepted directly from external clients. ### Workarounds If you cannot upgrade immediately, block requests that would be handled by Next.js if they contain the `Next-Resume` header at the edge.

CVE-2026-44579 Affected Next Versions

2 component(s)
Fixed Versions:
15.5.1616.2.5
Product / Package Ecosystem Affected Versions Fixed Version
next
npm/next
npm
≥ 15.0.0
< 15.5.16
15.5.16
next
npm/next
npm
≥ 16.0.0
< 16.2.5
16.2.5

References

GitHub Advisory / Wiki ADVISORY
https://github.com/vercel/next.js/security/advisories/GHSA-mg66-mrh9-m8jx
NVD — CVE-2026-44579 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-44579
Next Source Repository REPOSITORY
https://github.com/vercel/next.js
Next Release RELEASE
https://github.com/vercel/next.js/releases/tag/v15.5.16
Next Release RELEASE
https://github.com/vercel/next.js/releases/tag/v16.2.5

Frequently Asked Questions

What is CVE-2026-44579?
CVE-2026-44579 is a security vulnerability in Next involving Next.js vulnerable to Denial of Service via connection exhaustion in applications using Cache Components under CWE-770: Allocation of Resources Without Limits or Throttling.
Which Next versions are affected?
Affected versions include releases prior to 15.5.16, 16.2.5 across affected packages: next.
What version fixes CVE-2026-44579?
Upgrading to 15.5.16, 16.2.5 (or the latest patched release for your respective branch) resolves the vulnerability.
Is next affected?
Yes, next is affected in releases prior to 15.5.16, 16.2.5. Upgrade your dependency to 15.5.16, 16.2.5 or later.
What is the CVSS score of CVE-2026-44579?
CVE-2026-44579 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2026-44579?
CVE-2026-44579 is classified under CWE-770: Allocation of Resources Without Limits or Throttling (The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.).
How can I check npm dependencies for CVE-2026-44579?
Run the dependency tree command: 'npm ls next'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-mg66-mrh9-m8jx",
  "modified" : "2026-05-14T20:38:23Z",
  "published" : "2026-05-11T15:56:24Z",
  "aliases" : [ "CVE-2026-44579" ],
  "summary" : "Next.js vulnerable to Denial of Service via connection exhaustion in applications using Cache Components",
  "details" : "### Impact\n\nApplications using Partial Prerendering through the Cache Components feature can be vulnerable to connection exhaustion through crafted POST requests to a server action. In affected configurations, a malicious request can trigger a request-body handling deadlock that leaves connections open for an extended period, consuming file descriptors and server capacity until legitimate users are denied service.\n\n### Fix\n\nWe now treat the header used for resuming Partial Prerendered requests as an internal-only header and strip it from untrusted incoming requests. This header should never be accepted directly from external clients.\n\n### Workarounds\n\nIf you cannot upgrade immediately, block requests that would be handled by Next.js if they contain the `Next-Resume` header at the edge.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "next"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "15.0.0"
      }, {
        "fixed" : "15.5.16"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "next"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "16.0.0"
      }, {
        "fixed" : "16.2.5"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/vercel/next.js/security/advisories/GHSA-mg66-mrh9-m8jx"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-44579"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/vercel/next.js"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/vercel/next.js/releases/tag/v15.5.16"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/vercel/next.js/releases/tag/v16.2.5"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-770" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-11T15:56:24Z",
    "nvd_published_at" : "2026-05-13T18:16:18Z"
  }
}